JP2009252993A - Calibrating method, moving body driving method and apparatus, aligning method and apparatus, pattern forming method and apparatus, and device method for manufacturing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure and compare the position of a moving body using two position measurement systems which have the same measuring direction and different installation positions, and to calibrate at least one of the two position measurement systems based upon the measurement results. <P>SOLUTION: While a stage WST is driven, X scales 39X<SB>1</SB>and 39X<SB>2</SB>provided on the stage WST are scanned using X heads 66<SB>5</SB>and 66<SB>0</SB>having measuring directions along an X axis to compare and measure an X position of the stage WST. Based upon measurement results thereof, calibration data for equalizing the measurement results of the X heads 66<SB>5</SB>and 66<SB>0</SB>are generated for XY positions of the stage WST. Calibration is performed using the calibration data to prevent a measurement error due to a difference of a scale from occurring even when X heads 66<SB>1</SB>to 66<SB>4</SB>and 66<SB>5</SB>to 66<SB>8</SB>are switched and used according to the Y position of the stage WST. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a calibration method, a moving body driving method and apparatus, an exposure method and apparatus, a pattern forming method and apparatus, and a device manufacturing method, and more specifically, calibrates the accuracy of driving a moving body along a predetermined plane. Calibration method, a mobile body driving method and apparatus for driving a mobile body using calibration data obtained by the calibration method, an exposure method using the mobile body driving method, and an exposure apparatus comprising the mobile body driving device, The present invention relates to a pattern forming method using a moving body driving method, a pattern forming apparatus including the moving body driving device, and a device manufacturing method using the pattern forming method.

  Conventionally, in a lithography process for manufacturing electronic devices (microdevices) such as semiconductor elements (integrated circuits, etc.), liquid crystal display elements, etc., a step-and-repeat type projection exposure apparatus (so-called stepper) or a step-and-scan type Projection exposure apparatuses (so-called scanning steppers (also called scanners)) are mainly used.

  In this type of exposure apparatus, in order to transfer a reticle (or mask) pattern to a plurality of shot regions on a substrate such as a wafer or a glass plate (hereinafter collectively referred to as a wafer), a wafer stage that holds the wafer includes: For example, it is driven in a two-dimensional direction by a linear motor or the like. The position of the wafer stage is generally measured by using a laser interferometer having high stability over a long period of time.

  However, in recent years, with the miniaturization of patterns due to higher integration of semiconductor elements, the requirement for overlay accuracy has become stricter, and air fluctuations caused by the temperature change and temperature gradient of the atmosphere on the beam path of the laser interferometer The resulting short-term fluctuations in measured values have become a major weight in the overlay budget.

  Therefore, an exposure apparatus that employs an encoder that has a measurement resolution comparable to or higher than that of a laser interferometer and is generally less susceptible to air fluctuations than an interferometer is proposed as a wafer stage position measurement device. (For example, refer to Patent Document 1).

  However, in the exposure apparatus disclosed in Patent Document 1, one side and the other side of the upper surface of the wafer stage with respect to a direction (Y-axis direction) parallel to a straight line connecting the optical axis of the projection optical system and the detection center of the alignment system. Are provided with a pair of X scales (diffraction gratings), and a pair of X head units of the encoder are arranged in a spaced relationship in the Y-axis direction. Therefore, in the exposure apparatus disclosed in Patent Document 1, the X head unit (head) is switched according to the position of the wafer stage in the Y-axis direction, and which X head unit is used. However, it is necessary to obtain the same measurement result regardless of the difference in scale used.

International Publication No. 2007/097379 Pamphlet

  From a first aspect, the present invention is a calibration method for calibrating the accuracy of driving a moving body along a predetermined plane including a first axis and a second axis that are orthogonal to each other, and driving the moving body Then, the second direction parallel to the second axis provided in a first direction parallel to the first axis on one surface substantially parallel to the predetermined plane of the movable body is defined as a periodic direction. Using a plurality of first and second encoder heads that can respectively face the first and second gratings, the position of the moving body in the second direction is measured, and the second surface is disposed on the one surface of the moving body. A step of measuring the position of the moving body in the first direction by using a pair of encoder heads facing each of the third and fourth gratings having the first direction provided apart in the direction as a periodic direction. And said first and second en Daheddo and using the measurement results of the pair of encoder heads, process and to create calibration data for calibrating at least one of the measurement values of the pair of encoder heads; a calibration method comprising the.

  According to this, the positional information on the plurality of first directions of the third and fourth gratings measured simultaneously by the pair of encoder heads, and the positional information (including in-plane rotation) of the movable body in a predetermined plane at the time of this measurement ) Is obtained. Then, using the obtained information (measurement results of the first and second encoder heads and the pair of encoder heads), calibration data for calibrating at least one measurement value of the pair of encoder heads is created. Therefore, by using this calibration data, the measurement value of the encoder head that faces at least one of the third and fourth gratings is calibrated, so that the measurement accuracy of the encoder head that faces the third grating and the fourth grating face each other. It is possible to match the measurement accuracy of the encoder head.

  From a second viewpoint, the present invention is a moving body driving method for driving a moving body along a predetermined plane including a first axis and a second axis orthogonal to each other, and is substantially parallel to the predetermined plane. The first and second gratings each having a periodic direction in a second direction parallel to the second axis and spaced apart in a first direction parallel to the first axis may be opposed to one surface of the movable body. The first and second head units including a plurality of first and second encoder heads are used to measure the position of the moving body in the second direction, and further, the second direction is provided on the one surface of the moving body. At least one of the third and fourth head units including a plurality of third and fourth encoder heads that can be opposed to the third and fourth gratings, respectively, that are spaced apart from each other and have the first direction as a periodic direction. Using Measuring the position of the moving body with respect to a direction; driving the moving body based on a measurement result of the measuring step and calibration data created using the calibration method of the present invention; It is the moving body drive method containing this.

  According to this, the measurement result of the position of the moving body in the second direction measured using the first and second head units, and the first direction measured using at least one of the third and fourth head units. The moving body is driven based on the measurement result of the position of the moving body and the calibration data created by using the calibration method of the present invention. Therefore, it is possible to calibrate a measurement result including a measurement error due to the grating of at least one of the third and fourth head units using the calibration data. Thereby, the case where the 3rd head unit comprised from the 3rd encoder head which opposes the 3rd grating is used, and the case where the 4th head unit comprised from the 4th encoder head which opposes the 4th grating is used. Thus, the measurement accuracy of the position measurement of the moving body can be matched. Therefore, even when the encoder head is switched between the third and fourth head units, it is possible to always maintain the same driving accuracy of the moving body.

  According to a third aspect of the present invention, there is provided an exposure method for forming a pattern on an object by irradiating an energy beam, wherein the moving body driving method of the present invention is used to form the pattern. An exposure method includes a step of driving a moving body that holds an object.

  According to this, in order to form the pattern on the object by irradiating the energy beam, the moving body holding the object is driven using the moving body driving method of the present invention. Therefore, it becomes possible to form a pattern on the object with high accuracy.

  According to a fourth aspect of the present invention, there is provided a pattern forming method for forming a pattern on an object, wherein the object is held by using the moving body driving method of the present invention to form the pattern. A pattern forming method including a step of driving a body along a predetermined plane.

  According to this, in order to form a pattern on the object, the moving body holding the object is driven using the moving body driving method of the present invention. Thereby, it becomes possible to form a pattern on the object with high accuracy.

  According to a fifth aspect of the present invention, there is provided a device manufacturing method comprising: a step of forming a pattern on an object using the pattern forming method of the present invention; and a step of processing the object on which the pattern is formed. Is the way.

  According to a sixth aspect of the present invention, there is provided a moving body drive apparatus that drives a moving body along a predetermined plane including a first axis and a second axis that are orthogonal to each other, and is substantially parallel to the predetermined plane. The first and second gratings each having a periodic direction in a second direction parallel to the second axis and spaced apart in a first direction parallel to the first axis may be opposed to one surface of the movable body. First and second head units which have a plurality of first and second encoder heads and measure the position of the moving body in the second direction; spaced apart in the second direction on the one surface of the moving body; It has a plurality of third and fourth encoder heads that can respectively face the third and fourth gratings having the first direction as a periodic direction, and measures the position of the moving body in the first direction. Third and fourth head units; the present invention A storage device that stores calibration data created by using a calibration method; a measurement result of at least one of the first and second head units and the third and fourth encoder units; and the calibration data. And a driving device for driving the moving body.

  According to this, it is measured by the driving device using the measurement result of the position of the moving body in the second direction measured using the first and second head units and at least one of the third and fourth head units. The moving body is driven based on the measurement result of the position of the moving body in the first direction and the calibration data created using the calibration method of the present invention. In this case, it is possible to calibrate the measurement result including the measurement error due to the grating of at least one of the third and fourth head units using the calibration data. Thereby, the case where the 3rd head unit comprised from the 3rd encoder head which opposes the 3rd grating is used, and the case where the 4th head unit comprised from the 4th encoder head which opposes the 4th grating is used. Thus, the measurement accuracy of the position measurement of the moving body can be matched. Therefore, even when the encoder head is switched between the third and fourth head units, it is possible to always maintain the same driving accuracy of the moving body.

  According to a seventh aspect of the present invention, there is provided an exposure apparatus for irradiating an energy beam to form a pattern on an object, wherein a moving body that holds the object is arranged along a predetermined plane in order to form the pattern. It is an exposure apparatus provided with the moving body drive device of the present invention.

  According to this, in order to form the pattern on the object by irradiating the energy beam, the moving body driving apparatus of the present invention drives the moving body holding the object along a predetermined plane. This makes it possible to form a pattern on the object with high accuracy.

  According to an eighth aspect of the present invention, there is provided a pattern forming apparatus for forming a pattern on an object, the movable body being movable while holding the object; a pattern generating apparatus for forming a pattern on the object; And a moving body driving device of the present invention that drives the moving body along a predetermined plane.

  According to this, in order to form a pattern on the object, the moving body holding the object is driven along a predetermined plane by the moving body driving device of the present invention. This makes it possible to form a pattern on the object with high accuracy.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to FIGS.

  FIG. 1 schematically shows a configuration of an exposure apparatus 100 according to an embodiment. The exposure apparatus 100 is a step-and-scan projection exposure apparatus, a so-called scanner. As will be described later, in the present embodiment, a projection optical system PL and a primary alignment system AL1 (see FIGS. 4 and 5, etc.) are provided. In the following, the direction parallel to the optical axis AX of the projection optical system PL is the Z-axis direction, and the direction parallel to the straight line connecting the optical axis AX and the detection center of the primary alignment system AL1 in the plane orthogonal to this is the Y-axis direction. The direction orthogonal to the Z axis and the Y axis is defined as the X axis direction, and the rotation (tilt) directions around the X axis, the Y axis, and the Z axis are defined as the θx, θy, and θz directions, respectively.

  As shown in FIG. 1, the exposure apparatus 100 includes an illumination system 10, a reticle stage RST, a projection unit PU, a local immersion apparatus 8, a stage apparatus 50 having a wafer stage WST and a measurement stage MST, and a control system thereof. , Etc. The exposure apparatus 100 is configured in the same manner as the exposure apparatus disclosed as an embodiment of International Publication No. 2007/097379 pamphlet, except for a part. In FIG. 1, wafer W is placed on wafer stage WST.

  The illumination system 10 includes a light source, an illuminance uniformizing optical system including an optical integrator, a reticle blind, and the like (both not shown) as disclosed in, for example, US Patent Application Publication No. 2003/0025890. And an illumination optical system. The illumination system 10 illuminates the slit-shaped illumination area IAR on the reticle R defined by the reticle blind (masking system) with illumination light (exposure light) IL with substantially uniform illuminance. Here, as an example of the illumination light IL, ArF excimer laser light (wavelength 193 nm) is used.

  On reticle stage RST, reticle R having a circuit pattern or the like formed on its pattern surface (lower surface in FIG. 1) is fixed, for example, by vacuum suction. The reticle stage RST can be finely driven in the XY plane by a reticle stage drive system 11 (not shown in FIG. 1, refer to FIG. 7) including, for example, a linear motor, etc. In the Y-axis direction) at a predetermined scanning speed.

  Position information in the XY plane of reticle stage RST (including rotation information in the θz direction) is transferred by reticle laser interferometer (hereinafter referred to as “reticle interferometer”) 116 to movable mirror 15 (actually in the Y-axis direction). Through a Y-moving mirror (or retro reflector) having an orthogonal reflecting surface and an X moving mirror having a reflecting surface orthogonal to the X-axis direction), detection is always performed with a resolution of, for example, about 0.25 nm. Is done. The measurement value of reticle interferometer 116 is sent to main controller 20 (not shown in FIG. 1, refer to FIG. 7).

  Projection unit PU is arranged below reticle stage RST in FIG. The projection unit PU includes a lens barrel 40 and a projection optical system PL held in the lens barrel 40. As projection optical system PL, for example, a refractive optical system including a plurality of optical elements (lens elements) arranged along optical axis AX parallel to the Z-axis direction is used. The projection optical system PL is, for example, both-side telecentric and has a predetermined projection magnification (for example, 1/4 times, 1/5 times, or 1/8 times). For this reason, when the illumination area IAR on the reticle R is illuminated by the illumination system 10, the illumination light that has passed through the reticle R arranged so that the first surface (object surface) and the pattern surface of the projection optical system PL substantially coincide with each other. The reduced image of the circuit pattern of the reticle R in the illumination area IAR (a reduced image of a part of the circuit pattern) is passed through the projection optical system PL (projection unit PU) by the IL on the second surface (image surface) side. And is formed in an area IA (hereinafter also referred to as an exposure area) IA conjugate to the illumination area IAR on the wafer W having a surface coated with a resist (sensitive agent). Then, by synchronous driving of reticle stage RST and wafer stage WST, reticle R is moved relative to illumination area IAR (illumination light IL) in the scanning direction (Y-axis direction) and exposure area IA (illumination light IL). By moving the wafer W relative to the scanning direction (Y-axis direction), scanning exposure of one shot area (partition area) on the wafer W is performed, and a reticle pattern is transferred to the shot area. . That is, in this embodiment, a pattern is generated on the wafer W by the illumination system 10, the reticle R, and the projection optical system PL, and the pattern is formed on the wafer W by exposure of the sensitive layer (resist layer) on the wafer W by the illumination light IL. Is formed.

  In the exposure apparatus 100 of the present embodiment, the local immersion apparatus 8 is provided as described above in order to perform immersion exposure. The local liquid immersion device 8 includes a liquid supply device 5, a liquid recovery device 6 (both not shown in FIG. 1, refer to FIG. 7), a liquid supply tube 31A, a liquid recovery tube 31B, a nozzle unit 32, and the like. As shown in FIG. 1, the nozzle unit 32 holds an optical element on the most image plane side (wafer W side) constituting the projection optical system PL, here a lens (hereinafter also referred to as “tip lens”) 191. It is suspended and supported by a main frame (not shown) that holds the projection unit PU so as to surround the lower end portion of the lens barrel 40. In the present embodiment, as shown in FIG. 1, the lower end surface of the nozzle unit 32 is set substantially flush with the lower end surface of the front lens 191. Further, the nozzle unit 32 is connected to the supply port and the recovery port of the liquid Lq, the lower surface on which the wafer W is disposed and provided with the recovery port, and the supply connected to the liquid supply tube 31A and the liquid recovery tube 31B, respectively. A flow path and a recovery flow path are provided. As shown in FIG. 4, the liquid supply pipe 31 </ b> A and the liquid recovery pipe 31 </ b> B are inclined by approximately 45 ° with respect to the X-axis direction and the Y-axis direction in plan view (viewed from above). The arrangement is symmetric with respect to a straight line (hereinafter referred to as a reference axis) LV parallel to the Y axis that connects the optical axis AX and the detection center of the primary alignment system AL1. In FIG. 4, symbol UP indicates an unloading position where the center of wafer stage WST is positioned when the wafer is unloaded on wafer stage WST, and symbol LP indicates the center of wafer stage WST when the wafer is loaded onto wafer stage WST. Indicates the loading position.

  The liquid supply pipe 31A is connected to the liquid supply apparatus 5 (not shown in FIG. 1, see FIG. 7), and the liquid recovery pipe 31B is connected to the liquid recovery apparatus 6 (not shown in FIG. 1, see FIG. 7). Here, the liquid supply device 5 includes a tank for storing the liquid, a pressurizing pump, a temperature control device, a valve for controlling the flow rate of the liquid, and the like. The liquid recovery device 6 includes a tank for storing the recovered liquid, a suction pump, a valve for controlling the flow rate of the liquid, and the like.

  The main controller 20 controls the liquid supply device 5 (see FIG. 7) to supply liquid between the front lens 191 and the wafer W via the liquid supply pipe 31A. Then, the liquid recovery apparatus 6 (see FIG. 7) is controlled to recover the liquid from between the front lens 191 and the wafer W via the liquid recovery pipe 31B. At this time, the main controller 20 controls the liquid supply device 5 and the liquid recovery device 6 so that the amount of supplied liquid and the amount of recovered liquid are always equal. Accordingly, a certain amount of liquid Lq (see FIG. 1) is always exchanged and held between the front lens 191 and the wafer W, whereby the liquid immersion region 14 is formed. In addition, even when a measurement stage MST described later is positioned below the projection unit PU, the liquid immersion region 14 can be similarly formed between the tip lens 191 and the measurement table.

  In this embodiment, pure water that transmits ArF excimer laser light (light having a wavelength of 193 nm) (hereinafter, simply referred to as “water” unless otherwise required) is used as the liquid. Note that the refractive index n of water with respect to ArF excimer laser light is approximately 1.44, and the wavelength of the illumination light IL is shortened to 193 nm × 1 / n = about 134 nm in water.

  As shown in FIG. 1, the stage apparatus 50 includes a wafer stage WST and a measurement stage MST disposed above the base board 12, and a measurement system 200 (see FIG. 7) that measures positional information of both stages WST and MST. And a stage drive system 124 (see FIG. 7) for driving both stages WST and MST. As shown in FIG. 7, the measurement system 200 includes an interferometer system 118, an encoder system 150, a surface position measurement system 180, and the like.

  Wafer stage WST and measurement stage MST are supported above base board 12 by a non-contact bearing (not shown) such as an air bearing with a clearance of about several μm. Both stages WST and MST can be driven independently by a stage drive system 124 (see FIG. 7) including a linear motor or the like.

  Wafer stage WST includes a stage main body 91 and a wafer table WTB mounted on stage main body 91, as shown in FIG. The wafer table WTB and the stage main body 91 are directed to the base board 12 in directions of six degrees of freedom (X, Y, Z, θx, etc.) by a drive system including a linear motor and a Z / leveling mechanism (including a voice coil motor). It can be driven to θy, θz).

  At the center of the upper surface of wafer table WTB, a wafer holder (not shown) for holding wafer W by vacuum suction or the like is provided. As shown in FIG. 2A, a circular opening that is slightly larger than the wafer W (wafer holder) is formed in the center on the outside of the wafer holder (wafer mounting region) and has a rectangular outer shape (contour). ) Having a plate (liquid repellent plate) 28. The surface of the plate 28 is subjected to a liquid repellency treatment with respect to the liquid Lq (a liquid repellent surface is formed). The plate 28 is fixed to the upper surface of the wafer table WTB so that the entire surface (or part) of the plate 28 is flush with the surface of the wafer W.

  The plate 28 has a first liquid-repellent region (first liquid-repellent plate) 28a having a rectangular outer shape (contour) in which the above-described circular opening is formed in the center, and a rectangular frame shape (annular) disposed around the plate 28. And a second liquid repellent region (second liquid repellent plate) 28b.

  A measurement plate 30 is provided at the + Y side end of the first liquid repellent plate 28a. The measurement plate 30 is provided with a reference mark FM at the center, and a pair of aerial image measurement slit patterns (slit-like measurement patterns) SL are provided on both sides of the reference mark FM in the X-axis direction. Corresponding to each aerial image measurement slit pattern SL, there is provided a light transmission system (not shown) for guiding the illumination light IL passing therethrough to the outside of wafer stage WST (a light receiving system provided in measurement stage MST described later). It has been.

On the second liquid repellent plate 28b, a scale used in an encoder system described later is formed. More specifically, Y scales 39Y ₁ and 39Y ₂ are formed in regions on one side and the other side of the second liquid repellent plate 28b in the X-axis direction (left and right direction in FIG. 2A). . The Y scales 39Y ₁ and 39Y ₂ are, for example, reflective type gratings (for example, diffraction gratings) in which the Y axis direction is a periodic direction in which grid lines 38 having the X axis direction as the longitudinal direction are arranged at a predetermined pitch in the Y axis direction. ).

Similarly, a region between one side and the other side of the second liquid repellent plate 28b in the Y-axis direction (upper and lower sides in the drawing in FIG. 2A) is sandwiched between Y scales 39Y ₁ and 39Y ₂ . X scales 39X ₁ and 39X ₂ are formed, respectively. The X scales 39X ₁ and 39X ₂ are, for example, reflection type gratings (for example, diffraction gratings) in which the X-axis direction is a periodic direction in which grid lines 37 having a longitudinal direction in the Y-axis direction are arranged in the X-axis direction at a predetermined pitch. ).

  The pitch of the grid lines 37 and 38 is set to 1 μm, for example. In FIG. 2A and other figures, the pitch of the grating is shown larger than the actual pitch for the convenience of illustration.

  In order to protect the diffraction grating, it is also effective to cover it with a glass plate having a low thermal expansion coefficient having liquid repellency. Here, as the glass plate, a glass plate having the same thickness as the wafer, for example, a thickness of 1 mm can be used, and the wafer table so that the surface of the glass plate is the same height (level) as the wafer surface. Installed on top of WST.

  Further, as shown in FIG. 2A, a reflecting surface 17a and a reflecting surface 17b used in an interferometer system to be described later are formed on the −Y end surface and the −X end surface of wafer table WTB.

  The measurement stage MST includes a stage main body 92 that is driven in the XY plane by a linear motor (not shown) and the like, and a measurement table MTB mounted on the stage main body 92. As with wafer stage WST, measurement stage MST is also configured to be capable of being driven in directions of six degrees of freedom (X, Y, Z, θx, θy, θz) with respect to base board 12 by a drive system (not shown).

  In FIG. 7, a stage drive system 124 is shown including a drive system for wafer stage WST and a drive system for measurement stage MST.

  Various measurement members are provided on the measurement table MTB (and the stage main body 92). As this measuring member, for example, as shown in FIG. 2B, an illuminance unevenness sensor 94, an aerial image measuring instrument 96, a wavefront aberration measuring instrument 98, an illuminance monitor (not shown), and the like are provided. Further, the stage main body 92 is provided with a pair of light receiving systems (not shown) in an arrangement facing the above pair of light sending systems (not shown). In the present embodiment, each aerial image measurement slit pattern SL of measurement plate 30 on wafer stage WST is measured in a state where wafer stage WST and measurement stage MST are close to each other within a predetermined distance in the Y-axis direction (including a contact state). An aerial image measuring device 45 (see FIG. 7) is constructed in which the transmitted illumination light IL is guided by each light transmission system (not shown) and received by a light receiving element of each light receiving system (not shown) in the measurement stage MST. The

  Further, reflection surfaces 19a and 19b for interferometers are formed on the + Y end surface and the −X end surface of the measurement table MTB.

  A fiducial bar (hereinafter abbreviated as “FD bar”) 46 extending in the X-axis direction is attached to the −Y side surface of the measurement table MTB, as shown in FIG. . Reference gratings (for example, diffraction gratings) 52 having a periodic direction in the Y-axis direction are formed in the vicinity of one end and the other end in the longitudinal direction of the FD bar 46 in a symmetrical arrangement with respect to the center line CL. . A plurality of reference marks M are formed on the upper surface of the FD bar 46. As each reference mark M, a two-dimensional mark having a size detectable by an alignment system described later is used. The surface of the FD bar 46 and the surface of the measurement table MTB are also covered with a liquid repellent film.

In the exposure apparatus 100 of the present embodiment, as shown in FIGS. 4 and 5, the detection center is located at a position a predetermined distance from the optical axis AX of the projection optical system PL to the −Y side on the reference axis LV. A primary alignment system AL1 is disposed. Primary alignment system AL1 is fixed to the lower surface of the main frame (not shown). As shown in FIG. 5, secondary alignment systems AL2 ₁ and AL2 _{2 in} which detection centers are arranged almost symmetrically with respect to the reference axis LV on one side and the other side in the X-axis direction across the primary alignment system AL1. , AL2 ₃ and AL2 ₄ are provided. The secondary alignment systems AL2 _{1 to} AL2 ₄ are fixed to the lower surface of the main frame (not shown) via a movable support member, and the X-axis is used using the drive mechanisms 60 _{1 to} 60 ₄ (see FIG. 7). The relative positions of these detection areas can be adjusted with respect to the direction.

In the present embodiment, for example, an image processing type FIA (Field Image Alignment) system is used as each of the alignment systems AL1, AL2 _{1 to} AL2 ₄ . Imaging signals from each of the alignment systems AL1, AL2 _{1 to} AL2 ₄ are supplied to the main controller 20 via a signal processing system (not shown).

As shown in FIG. 3, interferometer system 118 projects an interferometer beam (measurement beam) onto each of reflecting surfaces 17a and 17b, receives the reflected light, and measures the position of wafer stage WST. The interferometer 16, the three X interferometers 126 to 128, the Y interferometer 18 that measures the position of the measurement stage MST, and the X interferometer 130 are provided. More specifically, the Y interferometer 16 reflects at least three length measuring beams parallel to the Y axis including a pair of length measuring beams B4 ₁ and B4 ₂ symmetric with respect to the reference axis LV, and a movable mirror 41 described later. Project to. Further, as shown in FIG. 3, the X interferometer 126 includes a pair of length measuring beams symmetrical with respect to a straight line (hereinafter referred to as a reference axis) LH parallel to the X axis orthogonal to the optical axis AX and the reference axis LV. At least three measurement beams including B5 ₁ and B5 ₂ parallel to the X axis are projected onto the reflection surface 17b. Further, the X interferometer 127 includes at least a length measuring beam B6 having a length measuring axis as a straight line LA (hereinafter referred to as a reference axis) LA parallel to the X axis orthogonal to the reference axis LV at the detection center of the alignment system AL1. Two measurement beams parallel to the Y axis are projected onto the reflecting surface 17b. Further, the X interferometer 128 projects a measurement beam B7 parallel to the Y axis onto the reflection surface 17b.

  Position information from each interferometer of the interferometer system 118 is supplied to the main controller 20. Based on the measurement result of Y interferometer 16 and X interferometer 126 or 127, main controller 20 adds rotation information (that is, pitching information) in the θx direction in addition to the X and Y positions of wafer table WTB (wafer stage WST). , Θy direction rotation information (that is, rolling information), and θz direction rotation information (that is, yawing information) can also be obtained.

  As shown in FIG. 1, a movable mirror 41 having a concave reflecting surface is attached to the side surface on the −Y side of the stage main body 91. As can be seen from FIG. 2A, the movable mirror 41 is designed such that the length in the X-axis direction is longer than the reflecting surface 17a of the wafer table WTB.

  A pair of Z interferometers 43A and 43B that constitute part of the interferometer system 118 (see FIG. 7) are provided facing the movable mirror 41 (see FIGS. 1 and 3). The Z interferometers 43A and 43B project two length measuring beams B1 and B2 through the movable mirror 41, for example, to fixed mirrors 47A and 47B fixed to a frame (not shown) that supports the projection unit PU. And each reflected light is received and the optical path length of length measuring beam B1, B2 is measured. Based on the result, main controller 20 calculates the position of wafer stage WST in the four degrees of freedom (Y, Z, θy, θz) direction.

  In the present embodiment, position information (including rotation information in the θz direction) of wafer stage WST (wafer table WTB) in the XY plane is mainly measured using encoder system 150 described later. Interferometer system 118 is used when wafer stage WST is positioned outside the measurement area of encoder system 150 (for example, near the unloading position or the loading position). In addition, the interferometer system 118 is used supplementarily when correcting (calibrating) long-term fluctuations in the measurement results of the encoder system 150 (for example, due to deformation of the scale over time). Of course, interferometer system 118 and encoder system 150 may be used in combination to measure all position information of wafer stage WST (wafer table WTB).

  As shown in FIG. 3, the Y interferometer 18 and the X interferometer 130 of the interferometer system 118 project interferometer beams (measurement beams) onto the reflecting surfaces 19 a and 19 b, and each reflected light is projected. By receiving the light, position information of the measurement stage MST (for example, including at least position information in the X-axis and Y-axis directions and rotation information in the θz direction) is measured, and the measurement result is supplied to the main controller 20. .

  In the exposure apparatus 100 of the present embodiment, a plurality of encoder systems 150 are configured to measure the position (X, Y, θz) in the XY plane of the wafer stage WST independently of the interferometer system 118. A head unit is provided.

As shown in FIG. 4, four head units 62A, 62B, 62C, and 62D are arranged on the + X side, + Y side, -X side of the nozzle unit 32, and -Y side of the primary alignment system AL1, respectively. ing. Further, head units 62E and 62F are respectively arranged on both outer sides in the X-axis direction of the alignment systems AL1, AL2 _{1 to} AL2 ₄ . These head units 62A to 62D are fixed in a suspended state to a main frame (not shown) that holds the projection unit PU via support members.

As shown in FIG. 5, each of the head units 62A and 62C includes a plurality of (here, five) Y heads 65 _{1 to} 65 ₅ and Y heads 64 ₁ to 64 ₅ . Here, the Y heads 65 _{2 to} 65 ₅ and the Y heads 64 ₁ to 64 ₄ are arranged on the reference axis LH with an interval WD. Y heads 65 ₁ and Y head 64 ₅ are disposed on the -Y side position of a predetermined distance apart nozzle units 32 in the -Y direction from the reference axis LH. The distance in the X-axis direction between the Y heads 65 ₁ and 65 _{2 and} between the Y heads 64 ₄ and 64 ₅ is also set to WD. The Y heads 65 _{1 to} 65 ₅ and the Y heads 64 ₅ to 64 ₁ are disposed symmetrically with respect to the reference axis LV. Hereinafter, Y heads 65 _{1 to} 65 ₅ and Y heads 64 ₁ to 64 ₅ are also referred to as Y head 65 and Y head 64, respectively, as necessary.

The head unit 62A uses a Y scale 39Y ₁ to measure a Y-axis position (Y position) of the wafer stage WST (wafer table WTB) in the Y-axis direction (Y-lens here) Y linear encoder 70A (FIG. 7). To configure). Similarly, the head unit 62C constitutes a multi-lens (here, 5 eyes) Y linear encoder 70C (see FIG. 7) that measures the Y position of the wafer stage WST (wafer table WTB) using the Y scale 39Y ₂ . To do. In the following, the Y linear encoder is abbreviated as “Y encoder” or “encoder” as appropriate.

Here, the interval WD in the X-axis direction of the five Y heads 65 and 64 (more precisely, the projection points on the scale of the measurement beams emitted by the Y heads 65 and 64) provided in the head units 62A and 62C, respectively, is The Y scales 39Y ₁ and 39Y ₂ are set slightly narrower than the width in the X-axis direction (more precisely, the length of the grid lines 38). Therefore, for example, at the time of exposure, at least one of the five Y heads 65 and 64 always faces the corresponding Y scales 39Y ₁ and 39Y ₂ (projects a measurement beam).

As shown in FIG. 5, the head unit 62B is arranged on the + Y side of the nozzle unit 32 (projection unit PU), and a plurality of (here, four) X heads 66 arranged on the reference axis LV with a spacing WD. It is equipped with a _{5-66 8.} Further, head unit 62D is arranged on the -Y side of primary alignment system AL1, a plurality which are arranged at a distance WD on reference axis LV (four in this case) and a X heads 66 ₁ to 66 _4. Hereinafter, the X heads 66 _{5 to} 66 ₈ and the X heads 66 _{1 to} 66 ₄ are also referred to as the X head 66 as necessary.

The head unit 62B uses the X scale 39X ₁ to measure the position (X position) of the wafer stage WST (wafer table WTB) in the X-axis direction (here, four eyes) X linear encoder 70B (FIG. 7). Further, head unit 62D uses the X scale 39X _2, multiview that measures the X-position of wafer stage WST (wafer table WTB) (here 4 eyes) constituting the X linear encoder 70D (refer to FIG. 7) . In the following, the X linear encoder is abbreviated as “X encoder” or “encoder” as appropriate.

Here, the interval WD in the Y-axis direction between adjacent X heads 66 (more precisely, projection points on the scale of the measurement beam emitted by the X head 66) included in the head units 62B and 62D is the X scale 39X ₁ , (more precisely, the length of the grating lines 37) 39X ₂ in the Y-axis direction of the width is set narrower than. Therefore, for example, at the time of exposure, at least one of the X heads 66 included in the head units 62B and 62D always faces the corresponding X scales 39X ₁ and 39X ₂ (projects a measurement beam). ).

The distance between the most + Y side X heads 66 ₄ of the most -Y side of the X heads 66 ₅ and the head unit 62D of the head unit 62B is the movement of the Y-axis direction of wafer stage WST, between the two X heads The width of the wafer table WTB is set to be slightly narrower than the width in the Y-axis direction so that it can be switched (connected).

Head unit 62E, as shown in FIG. 5, a Y heads _67i to 674 ₄ of the plurality of (four in this case). Here, the three Y heads 67 _{1 to} 67 ₃ are arranged on the reference axis LA on the −X side of the secondary alignment system AL 21 ₁ at substantially the same interval as the interval WD. Y head 67 _4, from the reference axis LA in the + Y direction are disposed on the + Y side of secondary alignment system AL2 ₁ a predetermined distance away. The distance in the X-axis direction between the Y heads 67 ₃ and 67 ₄ is also set to WD.

Head unit 62F is equipped with a Y heads 68 ₁ to 68 ₄ of a plurality (four in this case). These Y heads 68 ₁ to 68 _4, with respect to the reference axis LV, is disposed on the Y head 67 _{4-67 1} and symmetrical position. Hereinafter, if necessary, the Y heads _67i to 674 ₄ and Y heads 68 ₁ to 68 _4, each describing both Y heads 67 and Y heads 68.

At the time of alignment measurement, at least one Y head 67 and 68 faces the Y scales 39Y ₂ and 39Y ₁ , respectively. The Y position (and θz rotation) of wafer stage WST is measured by Y heads 67 and 68 (that is, Y encoders 70E and 70F constituted by Y heads 67 and 68).

In the present embodiment, the Y heads 67 ₃ and 68 ₂ adjacent to the secondary alignment systems AL2 ₁ and AL2 ₄ in the X-axis direction are used as a pair of reference grids of the FD bar 46 when measuring the baseline of the secondary alignment system. The Y position of the FD bar 46 is measured at the position of each reference grating 52 by the Y heads 67 ₃ and 68 ₂ that face each other and the pair of reference gratings 52. Hereinafter, encoders configured by Y heads 67 ₃ and 68 ₂ respectively facing the pair of reference gratings 52 are referred to as Y linear encoders 70E ₂ and 70F ₂ (see FIG. 7). For identification purposes, Y encoders composed of Y heads 67 and 68 facing Y scales 39Y ₂ and 39Y ₁ are referred to as Y encoders 70E ₁ and 70F ₁ .

The measurement values of the six linear encoders 70A to 70F described above are supplied to the main controller 20, and the main controller 20 includes three of the linear encoders 70A to 70D or the linear encoders 70E ₁ , 7F ₁ , 70B and 70D. The position of the wafer table WTB in the XY plane is controlled based on the three measured values, and the θz direction of the FD bar 46 (measurement stage MST) is determined based on the measured values of the linear encoders 70E ₂ and 70F _2. Control the rotation of

Further, in the present embodiment, the X head 66 ₀ used for calibrating the X encoders 70B and 70D is provided on the + Y side of the X head 66 _{4 with} a gap WD. As described below, X head 66 _0, together with the X heads 66 ₅ faces X scale 39X _1, is installed in a position facing X scale 39X _2. Here, X head 66 _0, 66 ₅ of the distance in the Y-axis direction is set to be substantially equal to the X scales 39X _1, the 39X ₂ distance in the Y-axis direction.

As shown in FIG. 6, the exposure apparatus 100 of the present embodiment includes a multipoint focal position detection system (90a, 90b) for measuring the surface position of the entire surface of the wafer W placed on the wafer stage WST. A plurality of Z heads (72a to 72d, 74 ₁ to 74 ₅ , 76 _{1 to} 76 ₅ ) constituting the surface position measuring system 180 for measuring the position of the wafer stage WST in the Z-axis direction and the tilt direction are provided. ing. As shown in FIG. 7, the Z head is connected to the main controller 20 via a signal processing / selecting device 170 constituting the surface position measuring system 180. Note that details of the multipoint focal position detection system and the surface position measurement system 180 are disclosed in the pamphlet of International Publication No. 2007/097379, and thus detailed description thereof is omitted. In addition, in FIG. 6 and the like, a plurality of detection points irradiated with the detection beams are not individually illustrated, but as elongated detection areas (beam areas) AF extending in the X-axis direction between the irradiation system 90a and the light receiving system 90b. It is shown.

  FIG. 7 shows the main configuration of the control system of the exposure apparatus 100. This control system is mainly configured of a main control device 20 composed of a microcomputer (or a workstation) for overall control of the entire apparatus. In FIG. 7, various sensors provided on the measurement stage MST such as the illuminance unevenness sensor 94, the aerial image measuring device 96, and the wavefront aberration measuring device 98 described above are collectively shown as a sensor group 99.

  In the present embodiment, main controller 20 uses encoder system 150 (see FIG. 7) to at least in the effective stroke area of wafer stage WST, that is, in the area where wafer stage WST moves for alignment and exposure operations. The position coordinates in the direction of three degrees of freedom (X, Y, θz) can be measured.

  As each encoder head, for example, an interference type encoder head disclosed in International Publication No. 2007/097379 pamphlet is used. In this type of encoder head, two measurement lights are projected onto a corresponding scale, the respective return lights are combined into one interference light, and the intensity thereof is measured using a photodetector.

In the present embodiment, by adopting the arrangement of the encoder head as described above, at least one X head 66 is always provided on the X scale 39X ₁ or 39X ₂ and at least one Y head 65 (or on the Y scale 39Y _1). 68), at least one of Y heads 64 in the Y scales 39Y ₂ (or 67) opposes respectively. The encoder head facing the scale has the position of the wafer stage WST (more precisely, the measurement beam) in each measurement direction with reference to the position of the head (more precisely, the position of the projection point of the measurement beam). Measure the position of the scale to be projected. The measurement result is supplied to the main controller 20 as the measurement result of the encoder 70A, 70C and 70B or 70D (or the encoder 70E ₁ , 70F ₁ and 70B or 70D).

Main controller 20 determines the position (X, Y, θz) of wafer stage WST in the XY plane based on the measurement results of encoders 70A, 70C and 70B or 70D (or encoders 70E ₁ , 70F ₁ and 70B or 70D). ) Is calculated. Here, the measurement values (represented as C _X , C _Y1 , and C _Y2 ) of the X head 66 and the Y heads 65 and 64 (or 68 and 67, respectively) are at the position (X, Y, θz) of the wafer stage WST. On the other hand, it depends on the following expressions (1) to (3).

C _X = (p _X −X) cos θz + (q _X −Y) sin θz (1)
C _Y1 = − (p _Y1 −X) sin θz + (q _Y1 −Y) cos θz (2)
C _Y2 = − (p _Y2 −X) sin θz + (q _Y2 −Y) cos θz (3)
However, (p _X , q _X ), (p _{Y 1} , q _{Y 1} ), (p _{Y 2} , q _{Y 2} ) are X, 66, Y (or 68), and Y (or 67) X, 66, respectively. Y installation position (more precisely, the X and Y positions of the projection point of the measurement beam). Therefore, main controller 20 substitutes measurement values C _X , C _Y1 , and _{CY 2} of the three heads into simultaneous equations (1) to (3), and solves them to obtain them in the XY plane of wafer stage WST. The position (X, Y, θz) is calculated. According to this calculation result, drive control of wafer stage WST is performed.

Further, main controller 20 controls the rotation of FD bar 46 (measurement stage MST) in the θz direction based on the measurement values of linear encoders 70E ₂ and 70F ₂ . Here, the measured values of the linear encoders 70E ₂ and 70F ₂ (represented as C _Y1 and _CY2 respectively) are expressed by equations (2) and (3) with respect to the (X, Y, θz) position of the FD bar 46. Depends on. Accordingly, the θz position of the FD bar 46 is obtained from the measured values C _Y1 and C _{Y2 as in} the following equation (4).

sin θz = − (C _Y1 −C _Y2 ) / (p _Y1 −p _Y2 ) (4)
However, for the sake of simplicity, q _Y1 = q _Y2 is assumed.

  Main controller 20 calculates the XY position of wafer stage WST from the measured values of at least three encoder heads facing the scale. Here, due to the arrangement of the encoder head employed in the present embodiment, the head facing the scale is sequentially replaced with the adjacent head as the wafer stage WST moves. Therefore, main controller 20 sequentially switches the encoder head that monitors the measurement value to calculate the stage position to the adjacent head according to the movement of wafer stage WST.

For example, assume that wafer stage WST has moved in the + X direction as shown in FIG. In this case, as indicated by arrow e ₁ , Y head 64 for measuring the Y position of wafer stage WST is switched from Y head 64 ₃ to Y head 64 ₄ . Further, as shown in FIG. 8B, it is assumed that wafer stage WST has moved in the + Y direction. This case, as indicated by arrow _{e 2,} X head 66 that measures the X-position of wafer stage WST, from X heads 66 ₅ to X head 66 _6, is switched. Thus, Y head 64 (and 65) is sequentially switched to the adjacent head as wafer stage WST moves in the X-axis direction. Also, the X head 66 is sequentially switched to the adjacent head as the wafer stage WST moves in the Y-axis direction.

  Since the encoder detects the relative displacement, the reference position must be determined in order to calculate the absolute displacement (that is, the position). Therefore, when the head is switched, the measured value of the head used after the switching, that is, the reference position is reset. This process of resetting the measurement values performed at the time of head switching is also called a linkage process.

  As described above, in order to calculate the (X, Y, θz) position of wafer stage WST, measurement values of at least three heads are required. Therefore, main controller 20 determines three heads (referred to as a second head set) including another head from position measurement using three heads (referred to as a first head set) in the head switching process. Switch to the position measurement to be used. At that time, main controller 20 first solves simultaneous equations (1) to (3) using the measurement values of the three encoder heads belonging to the first head set, and (X, Y, θz) of wafer stage WST. ) Calculate the position. Next, using the (X, Y, θz) position calculated here, the position is newly used from the same theoretical formula as the formulas (1) to (3) followed by the measurement value of the head to be newly used. Find the predicted value that the head should show. Then, main controller 20 sets the predicted value as a measured value (initial value) of a head to be newly used.

  With the above connecting process, the head switching process is completed while maintaining the result (X, Y, θz) of the position measurement of wafer stage WST. Thereafter, using the measurement values of the three heads used after switching, the same simultaneous equations as described above are solved to calculate the (X, Y, θz) position of wafer stage WST. Based on the result, wafer stage WST is driven and controlled.

  Next, a method for calibrating the X encoders 70B and 70D performed in the exposure apparatus 100 of the present embodiment will be described. Prior to the description of the calibration method, the reason why calibration is necessary will be described.

In exposure apparatus 100 of the present embodiment, since the movement stroke of wafer stage WST in the Y-axis direction is long, the position of wafer stage WST in the X-axis direction (Y position) according to the position (Y position) of wafer stage WST in the Y-axis direction ( The encoder used for the measurement of (X position) is properly used. That is, main controller 20 faces X scale 39X ₁ when wafer stage WST is located in the + Y side half of the movement stroke area in the Y-axis direction, ie, below projection unit PU ( The X position of wafer stage WST is measured using head unit 62B (X encoder 70B) having a head that projects a measurement beam. On the other hand, main controller 20 determines X scale 39X when wafer stage WST is positioned at the −Y side half of the movement stroke region in the Y-axis direction, that is, when it is positioned below alignment systems AL1, AL2 _{1 to} AL2 _4. The X position of wafer stage WST is measured using head unit 62D (X encoder 70D) having a head facing ₂ (projecting a measurement beam).

For example, as shown in FIG. 9, the wafer stage WST, the X heads 66 ₅ constituting the X encoder 70B is moved from the position facing X scale 39X ₁ in the -Y direction, X head 66 ₅ X scales 39X off the _1, X head 66 ₄ constituting the X encoder 70D comes to face the X scale 39X _2. At this time, the main controller 20, switching from X encoder 70B to 70D, i.e., switching from X heads 66 ₅ to scan different X scales to X head 66 ₄ is carried out.

X encoders 70B and 70D are both provided for measuring the X position of wafer stage WST. Therefore, even when measurement is performed using any of the X encoders 70B and 70D, the same measurement value must be output when wafer stage WST is at the same X position. That is, not only when switching between the X heads 66 ₅ and 66 ₄ shown in FIG. 9 but also before and after this switching, when the θz rotation of wafer stage WST is zero, X scale 39X ₁ and X scale 39X ₂ to, the measurement values of X head 66 facing each (66 either _{5-66 8)} and (either 66 ₁ -66 ₄₎ X heads 66 it is important to be consistent. Here, yawing θz of wafer stage WST can be calculated from the measured values of Y encoders 70A and 70C (Y heads 65 and 64). The separation distance between the Y heads 65 and 64 constituting the Y encoders 70A and 70C is substantially equal to the separation distance between the X heads 66 ₅ and 66 ₄ . Therefore, the θz rotation of the wafer stage WST can be measured with sufficient accuracy, thereby eliminating the influence of the θz rotation of the wafer stage WST on, for example, the discrepancy between the measured values of the X heads 66 ₅ and 66 ₄ described above.

However, it is difficult to manufacture the X scales 39X ₁ and 39X _{2 with} the same grating portion (grating), and the two X scales 39X ₁ and 39X have no mounting error when mounted on the wafer table WTB. ₂ is also difficult to install. Therefore, even if the X positions of all the X heads 66 coincide with each other and the θz rotation of the wafer stage WST is zero, the X scale 39X ₁ and the X scale 39X _{2 have} the same X position. It is considered that the measurement values of the X heads 66 that irradiate the measurement beam do not match. Actually, since the separation distance between the head unit 62B and the head unit 62D is long, it is difficult to maintain a state in which the X positions of all the X heads 66 coincide with each other over a long period of time. Furthermore, since the exposure apparatus 100 of the present embodiment employs the immersion exposure method, the immersion area 14 frequently travels on _one X scale 39X ₁ . Here, if the liquid Lq forming the liquid immersion region 14 is not completely recovered and remains on the scale even a little, it is generated by the thermal stress generated by the temperature difference between the liquid and the scale, or the liquid vaporizes. The X scale 39X ₁ is distorted by the heat of vaporization. For this reason, the distortion of the X scale 39X ₁ is particularly large compared to the X scale 39X ₂ , and is expected to further increase with the use of the apparatus. Therefore, it is difficult to guarantee the coincidence of the measured values of the X heads 66 ₅ and 66 ₄ over a long period of time.

For this reason, in the present embodiment, calibration data for calibrating the X encoders 70B and 70D is created according to the calibration method described below, and at least the X encoders 70B and 70D are used by using the created calibration data. Calibrate one. In the present embodiment, it is assumed that the measurement value of the X encoder 70B using the X scale 39X ₁ where a large distortion is expected is calibrated with reference to the measurement value of the X encoder 70D.

Upon this calibration, the X heads 66 ₀ described above provided for calibration is used. Since the X head 66 ₀ is installed at a distance WD from the adjacent X head 66 ₄ , for example, as shown in FIG. 9, the X heads 66 ₀ and 66 ₄ can simultaneously face the common X scale 39 X _2. . The X heads 66 ₄ and 66 ₅ are installed at positions facing the X scales 39X ₂ and 39X ₁ at the same time and individually so that they can be switched between the _two . Accordingly, as shown in FIG. 9, the X heads 66 _0, 66 ₄ faces X scale 39X _2, X head 66 ₅ may face the X scale 39X _1. (Also, the X head 66 ₀ can face the X scale 39X ₂ and the X heads 66 ₅ and 66 ₆ can face the X scale 39X _1. )
Further, X head 66 _0, as shown in FIG. 9, when the X heads 66 ₅ faces X scale 39X _1, is installed in a position facing X scale 39X _2. Here, X head 66 _0, 66 ₅ of the distance in the Y-axis direction is set to be substantially equal to the X scale 39X _2, the distance of 39X ₁ in the Y-axis direction.

<< First method for creating calibration data >>
Main controller 20 creates calibration data for calibrating X encoders 70B and 70D as follows. Here, as shown in FIG. 10 and FIG. 11, _four corresponding measurement lines indicated by symbols y ₁ , y ₂ , y ₃ , y ₄ are set on the X scales 39X ₁ , 39X _2. The sampling values of the X heads 66 ₅ and 66 ₀ are sampled at N sampling points on these measurement lines. Here, the measurement line indicated by the symbol y _j (j = 1 to 4) set on the X scale 39X ₁ and the symbol y _j set on the X scale 39X ₂ having the same value of _j The measurement line shown is a line in which the measurement beams of the X heads 66 ₅ and 66 ₀ are simultaneously scanned. These measurement lines are set to have the same y-coordinate value y _j on each xy _two- dimensional coordinate system, assuming an xy _two- dimensional coordinate system having the origins at the centers of the X scales 39X ₁ and 39X ₂ . . Of course, it is assumed that the θz rotation of wafer stage WST is adjusted to zero. Further, the interval between the jth and j + 1th measurement lines is assumed to be δy. In the exposure apparatus 100 of the present embodiment, δy has four sampling points (measurement points) at equal intervals in the Y-axis direction with reference to the effective widths of the X scales 39X ₁ and 39X ₂ (the length of the grid lines 37). It should be determined that it can be taken.

a. First, main controller 20 moves wafer stage WST to place X head 66 ₅ (measurement beam) at measurement point P (x ₁ , y ₁ ) on the upper surface of X scale 39X ₁ as shown in FIG. At the same time, the X head 66 ₀ (measurement beam) is made to face the measurement point Q (x ₁ , y ₁ ) on the upper surface of the X scale 39X ₂ . At this time, main controller 20 sets wafer stage WST to the reference state. That is, main controller 20 measures the Z position and θy direction position (rotation) of wafer stage WST using Z interferometers 43A and 43B, and uses Y interferometer 16 to perform the θx direction and θz of wafer stage WST. By measuring the position (rotation) in the direction, wafer stage WST is positioned at the reference position in the direction of four degrees of freedom (Z, θx, θy, θz).

b. Next, main controller 20 faces X scale 39X ₂ while maintaining the reference state of wafer stage WST and maintaining the Y position of wafer stage WST based on the measurement values of Y encoders 70A and 70C. Based on the measurement value of the X head 66 ₀ (encoder 70D), the wafer stage WST is scanned and driven in the −X direction at a constant speed as indicated by the white arrow in FIGS. At this time, since high control accuracy is required for yawing (rotation in the θz direction), control is performed based on the measurement values of the Y encoders 70A and 70C, instead of the Y interferometer 16. That is, when wafer stage WST is at the scanning drive start position shown in FIG. 10, yawing and waging of wafer stage WST are performed based on the measured values of Y heads 64 ₅ and 65 ₅ facing Y scales 39Y ₂ and 39Y ₁ , respectively. As the Y position is controlled and the wafer stage WST is moved in the −Y direction, the above-described joining process is sequentially performed between the adjacent Y heads 64 and 65. For example, when wafer stage WST is moved to the position shown in FIG. 11, the yawing and Y position of wafer stage WST are based on the measured values of Y heads 64 ₃ and 65 ₃ facing Y scales 39Y ₂ and 39Y ₁ , respectively. Be controlled.

The scan driving of the wafer stage WST, as shown in FIGS. 10 and 11, X head 66 ₅ of the measuring beam X scales 39X X-axis parallel to the measurement line with y-coordinate value y ₁ on ₁ At the same time, the measurement beam of the X head 66 ₀ is scanned along the measurement line parallel to the X axis having the y coordinate value y ₁ on the X scale 39X ₂ . During the scanning of both measurement beams, that is, during the constant speed movement of wafer stage WST, main controller 20 performs X head 66 ₀ and X head 66 ₀ at predetermined sampling intervals (or every time wafer stage WST moves by a constant distance δx). X head 66 ₅ measurements _{E 1 (x i, y j} ) and _{E 2 (x i, y j} ) (i = 1~N, j = 1) are simultaneously sampled.

c. Thereafter, the main control device 20 is connected to the a. And b. By alternately repeating the same procedure as was sampled at the same time, X head 66 ₀ and X head 66 ₅ measurements _{E 1 (x i, y j} ) and _{E 2 (x i, y j} ) (i = 1 ˜N, j = 2, 3, 4).
d. When the data sampling is completed, the main controller 20 determines the measured values E ₁ (x _i , y _j ) and E ₂ (x _i , y) of the two X heads 66 ₅ and 66 ₀ obtained at the respective sampling points. difference _{j) ΔE ij (i = 1~N} , j = 1~4 a), based on the following equation (5), is calculated.

ΔE _ij = ΔE (x _i , y _j ) = E ₁ (x _i , y _j ) −E ₂ (x _i , y _j ) (5)
d. Next, main controller 20 applies an appropriate interpolation formula to the obtained discrete data ΔE _ij to create calibration data (calibration function) ΔE (x, y) as a continuous function.

  Note that the calculation of the above-described equation (5) may be performed at the stage where sampling of all data is completed as described above, or immediately after the acquisition of data at each sampling point or the data for each measurement line. It may be performed every time measurement ends.

Further, main controller 20 moves wafer stage WST in the X-axis direction based on the measurement value of another measurement device, for example, X interferometer 126, instead of X head 66 ₀ (encoder 70D) facing X scale 39X _2. May be moved at a constant speed. Further, one of the yawing and Y position of wafer stage WST, for example, Y position when wafer stage WST is moved in the X-axis direction for the above-described sampling is controlled based on the measured value of Y interferometer 16. Also good. In this case, it is desirable to scan drive wafer stage WST at a low speed that is not affected by air fluctuations. Alternatively, the Z and θy positions of wafer stage WST may be measured using surface position measurement system 180.

In the first creation method described above, measurement for creating calibration data was performed with the yawing θz of wafer stage WST fixed at its reference position. Here, the reference position of yawing θz is the wafer stage WST in which the periodic direction of the diffraction grating of X scales 39X ₁ and 39X ₂ and the X-axis direction that is the measurement direction of X encoders 70B and 70D are parallel to each other. Of yaw θz. However, during measurement, sufficient drive accuracy of wafer stage WST may not be guaranteed. In such a case, a second creation method of calibration data described below may be adopted.

<< Second method for creating calibration data >>
In this second creation method, the X, Y, and θz positions of wafer stage WST obtained from the measurement results of encoders 70A, 70B, and 70C, and the X, Y, and θz positions obtained from the measurement results of encoders 70A, 70C, and 70D. Is a method for creating data for calibrating at least one of the measurement values of the X encoders 70B and 70D so as to match. Also in this second creation method, data sampling is performed in the same procedure as described above. Therefore, in the following, the difference from the first creation method, that is, the sampling result processing method for creating calibration data will be mainly described. Will be described.

  First, the X, Y, and θz positions of wafer stage WST obtained from the measurement results of encoders 70A, 70B, and 70C coincide with the X, Y, and θz positions obtained from the measurement results of encoders 70A, 70C, and 70D. A case where the X encoder 70B is calibrated will be described. (Conversely, the X encoder 70D can be calibrated according to a similar procedure.)

The main controller 20 measures the X positions of the X scales 39X ₁ and 39X ₂ with reference to the projection points of the respective measurement beams using the X heads 66 ₅ and 66 ₀ according to the same procedure as described above. . The measured values of the X heads 66 ₅ and 66 ₀ obtained at the measurement point (x _i , y _j ) are respectively _expressed as E _X1ij = E ₁ (x _i , y _j ), E _X2ij = E ₂ (x _i , y _j ). At the same time, the Y positions of the Y scales 39Y ₁ and 39Y ₂ with respect to the projection points of the respective measurement beams are measured using the Y encoders 70A and 70C (Y heads 65 and 64). The measured values of the Y heads 65 and ₆₄ are expressed as E _Y1ij and E _Y2ij , respectively.

Then, main controller 20, the measured value E _Y1ij measurements E _X2ij and Y heads 65 and 64 of the X heads 66 _0, the E _Y2ij, respectively, the left-hand side of the _C X of the formula (1) ~ (3), C Substituting into _Y1 and _CY2 , and solving simultaneous equations (1) to (3), the X, Y, and θz positions of wafer stage WST are obtained. Next, main controller 20 obtains the X, Y, and [theta] z, as well as into the equation (1), X X heads 66 _5, Y installation position (more precisely, the projection point of the measurement beam X, the Y _position), to predict the measurement value of _(p X, X head 66 ₅ are substituted into _{q X).} This predicted value is expressed as E _X1ij '. The predicted value E _X1ij 'is, X head 66 ₅ and Y heads 65 and 64 (encoders 70A, 70B, 70C) X of the wafer stage WST obtained from measurement values of, Y, is θz position, X head 66 ₀ and Y head 65 and 64 (encoders 70A, 70C, 70D) is the measurement value of X heads 66 ₅ to match X obtained from the measurement values of, Y, and θz position. Therefore, main controller 20 obtains difference ΔE _ij from ΔE _ij = E _X1ij −E _X1ij ′ instead of equation (5).

In the same manner as described above, main controller 20 obtains difference ΔE _ij for all sampling points, applies an appropriate interpolation formula to discrete data of difference ΔE _ij obtained at all sampling points, Create calibration data (calibration function) ΔE (x, y) as a continuous function of dimensions.

Note that the above-described calculation of ΔE _ij = E _X1ij −E _X1ij ′ may be performed at the stage where sampling of all data is completed, or data immediately after acquisition of data at each sampling point or data about each measurement line. It may be performed each time the measurement is completed.

Incidentally, when the aforementioned data sampling, instead of sampling the two measurement values of X head 66 _5, 66 ₀ during the movement of wafer stage WST, a wafer stage WST, when step movement (in this predetermined step distance interval It is not always necessary to move at a constant speed), and the above sampling may be performed at each step position (stop position).

  In the exposure apparatus 100 of this embodiment, the X encoders 70B and 70D are executed by the main controller 20 according to the above-described procedure, for example, when the exposure apparatus 100 is started, when processing of the wafer at the head of the lot is started, or when the exposure apparatus 100 is idle. Calibration data is generated.

In this embodiment, the following series of steps using wafer stage WST and measurement stage MST are performed according to the same procedure as disclosed in the embodiment of the above-mentioned pamphlet of International Publication No. 2007/097379. Processing operations are performed. That is,
a) When the wafer stage WST is at the unloading position UP shown in FIG. 4, when the wafer W is unloaded and moved to the loading position LP shown in FIG. 4, a new wafer W is placed on the wafer table WTB. To be loaded. In the vicinity of the unloading position UP and loading position LP, the position of wafer stage WST with six degrees of freedom is controlled based on the measurement value of interferometer system 118. At this time, the X interferometer 128 is used.

In parallel with the wafer exchange described above, the baseline measurement of the secondary alignment systems AL2 _{1 to} AL2 ₄ is performed. This baseline measurement is performed in a state in which the θz rotation of the FD bar 46 (measurement stage MST) is adjusted based on the measurement values of the encoders 70E ₂ and 70F ₂ described above, similarly to the method disclosed in the above international pamphlet. The alignment marks AL1 and AL2 _{1 to} AL2 ₄ are used to simultaneously measure the reference mark M on the FD bar 46 in each field of view.
b) After completion of the wafer exchange and the baseline measurement of the secondary alignment systems AL2 _{1 to} AL2 ₄ , the base of the prime alignment system AL1 that moves the wafer stage WST and detects the reference mark FM of the measurement plate 30 by the primary alignment system AL1. The first half of the line check is performed. Around this time, the origins of the encoder system 150 and the interferometer system 118 are reset (reset).
c) Thereafter, while measuring the position of the wafer stage WST in the direction of 6 degrees of freedom using the encoder system 118 and the Z heads 72a to 72d, the alignment systems AL1, AL2 _{1 to} AL2 ₄ are used to measure a plurality of positions on the wafer W. Alignment measurement for detecting an alignment mark in the sample shot area is performed, and in parallel with this, focus mapping (wafer W based on the measurement values of the Z heads 72a to 72d) using a multipoint AF system (90a, 90b) is performed. Measurement of the surface position (Z position) information). Here, after alignment measurement is started and before focus mapping is started, wafer stage WST and measurement stage MST are in a scrum state, and by movement of wafer stage WST for alignment measurement and focus mapping in the + Y direction, Liquid immersion area 14 is transferred from measurement stage MST to wafer stage WST. Then, when the measurement plate 30 reaches just below the projection optical system PL, the pair of alignment marks on the reticle R is measured by the slit scan method using the aerial image measurement device 45, and the latter half of the baseline check of the primary alignment system AL1. Is performed.
d) Thereafter, alignment measurement and focus mapping are continued.
e) When the alignment measurement and focus mapping are completed, the wafer is obtained by the step-and-scan method based on the position information of each shot area on the wafer obtained as a result of the alignment measurement and the latest alignment system baseline. A plurality of shot areas on W are exposed, and a reticle pattern is transferred. During the exposure operation, focus leveling control of the wafer W is performed based on information obtained by focus mapping. The Z and θy of the wafer being exposed are controlled based on the measured values of the Z heads 74 and 76, while θx is controlled based on the measured values of the Y interferometer 16.

  In the present embodiment, during the series of operations described above, main controller 20 drives calibration data generated in advance, for example, the latest calibration, when driving wafer stage WST based on the measurement value of X encoder 70B or 70D. The data, that is, the calibration function ΔE (x, y) is used to calibrate the measurement value of at least one of the X encoders 70B and 70D, here the X encoder 70B. That is, main controller 20 obtains correction value X according to the following equation (6), and drives and controls wafer stage WST according to the measured value after calibration.

X = X ₀ −ΔE (x, y) (6)
Here, X ₀ is an actual measurement of the X position obtained when a measurement beam is projected from one of the X heads 66 _{5 to} 66 ₈ constituting the X encoder 70B to a point (x, y) on the X scale 39X _1. Value. The (x, y) position of the measurement beam projection point is calculated from the (X, Y, θz) position of wafer stage WST.

  Main controller 20 may execute data sampling for creating calibration data in parallel with another operation such as during wafer alignment measurement or during exposure. However, in this case, since only partial sampling data can be obtained at one time, at least a part of the calibration data is updated after all the data is stored or after the data obtained for a certain period is stored. In addition, old data is appropriately deleted, and calibration data is updated using only new data. Thereby, the time required for calibration can be greatly shortened.

  In this case, data should be sampled and accumulated only in a time zone in which the acceleration is zero (stopping or moving at a constant speed) so as not to be affected by deformation of wafer table WTB (wafer stage WST) due to acceleration / deceleration. Calibration data can be collected even during scan exposure by sampling and accumulating data even when moving at a constant speed.

As described in detail above, according to the exposure apparatus 100 of the present embodiment, the wafer stage in the Y axis direction and the θz direction measured by the main controller 20 using the head units 62A and 62C (encoders 70A and 70C). Based on the measurement result of the position of WST, the measurement result of the position of wafer stage WST in the X-axis direction measured using at least one of head units 62B and 62D (encoders 70B and 70D), and the calibration data described above. Thus, wafer stage WST is driven via stage drive system 124. In this case, for example, when the position of wafer stage WST in the X-axis direction is measured using head unit 62B, the measurement data can be calibrated using calibration data, resulting from X scale 39X ₁ (grating). Measurement results including measurement errors can be calibrated. As a result, the head unit 62B composed of X heads 66 _{5 to} 66 ₈ facing the X scale 39X ₁ and the head unit composed of X heads 66 _{1 to} 66 ₄ facing the X scale 39X ₂ are used. The measurement accuracy of the position measurement of wafer stage WST can be matched with the case where 62D is used. Therefore, even when the encoder head is switched between the head units 62B and 62D and used, the same driving accuracy of the wafer stage WST can be maintained over a long period of time.

In the present embodiment, the calibration data is created as follows. In other words, wafer stage WST is driven, and the position of wafer stage WST in the Y-axis direction (and θz direction) is measured using a plurality of Y heads 65 and 64 that can face Y scales 39Y ₁ and 39Y ₂ , respectively. At the same time, the position of wafer stage WST in the X-axis direction is measured using X head 66 ₀ and X head 66 ₅ whose measurement direction is the X-axis direction facing X scales 39X ₁ and 39X ₂ , respectively. Thus, X head 66 ₀ and X head 66 ₅ and by simultaneously measuring (acquiring) has been X scales 39X _1, 39X plurality of position information in the X-axis direction ₂ (i.e., a plurality of the X scales 39X _1, 39X ₂ X position information at the measurement point) and position information (including in-plane rotation) in a predetermined plane of wafer stage WST at the time of measurement. Then, the obtained information (Y scales 39Y _1, 39Y _2, measurement of the Y head 65 and 64 respectively facing an X scales 39X _1, X head 66 ₅ and X heads 66 ₀ respectively opposed to 39X ₂ results) using, at least one of X heads 66 ₀ and X head 66 _5, in the present embodiment to create the calibration data for calibrating the measurement values of X head 66 _5. Here, the measurement value of the X head 66 ₅ includes an error component caused by the X scale 39X ₁ . Therefore, by calibrating the measurement value of the X head 66 facing the X scale 39X ₁ using the calibration data, the measurement accuracy of the X head 66 (encoder 66B) facing the X scale 39X ₁ and the X scale 39X _{2 are} corrected. It is possible to match the measurement accuracy of the X head 66 (encoder 66D) facing the head. Accordingly, even when the X encoders 70B and 70D (X heads 66 _{1 to} 66 ₄ and 66 _{5 to} 66 ₈ ) are switched according to the Y position of the wafer stage WST, the same measurement accuracy is maintained over a long period of time. It becomes possible to do.

  Further, according to the exposure apparatus 100 of the present embodiment, in order to form the pattern on the wafer W by irradiating the illumination light IL, the main controller 20 performs the encoders 70A and 70C and the encoder 70B as described above. , 70D, the wafer stage WST is driven via the stage drive system 124 based on the measurement result of the position of the wafer stage WST with respect to at least one of the above and 70D. Accordingly, it becomes possible to transfer and form a pattern (reticle pattern) on the wafer W with high accuracy. In the present embodiment, since immersion exposure is performed, it is possible to form a fine pattern on the wafer with high accuracy.

Since the exposure apparatus 100 of the present embodiment employs the immersion exposure method, it is expected that the distortion of the X scale 39X ₁ is large, that is, the measurement error of the X encoder 70B is larger than that of the X encoder 70D. Thus, the X encoder 70B is calibrated with reference to the X encoder 70D. However, in the case of a non-immersion type exposure apparatus, a large difference is not expected in the measurement accuracy of both encoders 70B and 70D. In such a case, for example, calibration data of measured values of both encoders 70B and 70D may be created with reference to an average value of measured values of the two X heads 66 ₅ and 66 ₀ .

In that case, the main controller 20 measures the X positions of the X scales 39X ₁ and 39X ₂ with reference to the projection points of the respective measurement beams using the X heads 66 ₅ and 66 ₀ according to the same procedure as described above. Then, the average AGV _ij (E ₁ , E ₂ ) = {E ₁ (x _i , y _j ) + E ₂ (Eq) of the respective measured values E ₁ (x _i , y _j ), E ₂ (x _i , y _j ) x _i , y _j )} / 2, and the difference ΔE _1ij = E ₁ (x _i , y _j ) −AGV _ij (E ₁ , E ₂ ), ΔE _2ij = E ₂ (X _i , y _j ) −AGV _ij (E ₁ , E ₂ ) is obtained. Then, main controller 20 applies an appropriate interpolation formula to discrete data ΔE _1ij and ΔE _2ij to create calibration data (calibration function) as a two-dimensional continuous function. The calibration functions obtained for both encoders 70B and 70D are denoted as ΔE ₁ (x, y) and ΔE ₂ (x, y).

Also in this case, if sufficient drive accuracy of wafer stage WST cannot be ensured during measurement, the X, Y, θz positions of wafer stage WST obtained from the measurement results of encoders 70A, 70B, and 70C, and encoder 70A , 70C, and 70D are calibrated so that the X, Y, and θz positions obtained from the measurement results coincide with their average values ( _denoted as X ₀ , Y ₀ , and θz ₀ ). You can do that.

That is, the main controller 20, the average value X _0, Y _0, with substituting [theta] z ₀ in equation _{(1), (p} X, _{q X)} X X heads 66 ₅ to, Y installation position (more accurately the X projection point of the measurement beam, by substituting Y position), to predict the measurement value of X heads 66 _5. This predicted value is expressed as E _X1ij '. Similarly, main controller 20 substitutes average values X ₀ , Y ₀ , and θz ₀ into equation (1), and at (p _X , q _X ), X and Y installation positions of X head 66 ₀ (more accurate). is by substituting X of the projection point of the measurement beam, the Y position), to predict the measurement value of X heads 66 _0. This predicted value is expressed as E _X2ij '. Then, main controller 20, in place of Equation (5), the difference ΔE _1ij = E _X1ij -E _X1ij 'with respect to the X heads 66 _5, a difference with respect to the X heads 66 ₀ ΔE _2ij = E _X2ij -E _{After obtaining X2ij} ′, an appropriate interpolation formula is applied to the discrete data ΔE _1ij and ΔE _2ij to create calibration data (calibration function) as a two-dimensional continuous function. The calibration functions obtained for the X heads 66 ₅ and 66 ₀ (encoders 70B and 70D) are expressed as ΔE ₁ (x, y) and ΔE ₂ (x, y), respectively.

In the series of operations described above, main controller 20 uses calibration functions ΔE ₁ (x, y) and ΔE ₂ (x, y) created in advance when driving wafer stage WST, The measurement results of the encoders 70B and 70D are calibrated. That is, main controller 20 obtains correction values X of X encoders 70B and 70D from X = X ₀₁ −ΔE ₁ (x, y) and X = X ₀₂ −ΔE ₂ (x, y), respectively. Then, wafer stage WST is driven and controlled in accordance with the measured value after calibration.

Here, X ₀₁ is an actual measurement of the X position obtained when the measurement beam is projected from any one of the X heads 66 _{5 to} 66 ₈ constituting the X encoder 70B to the point (x, y) on the X scale 39X _1. Value. X ₀₂ is an actual measurement of the X position obtained when a measurement beam is projected from _{one of} the X heads 66 _{1 to} 66 ₄ constituting the X encoder 70D to the point (x, y) on the X scale 39X _2. Value. The (x, y) position of the measurement beam projection point is calculated from the (X, Y, θz) position of wafer stage WST.

In the calibration method of this embodiment, X encoders 70B, in order to calibrate the 70D, the X heads 66 ₀ for calibration, from the most + Y side of the head 66 ₄ belonging to the head unit 62D, + Y direction distance WD Provided in position. Including the X head 66 _0. head unit 62D, as a component of X encoder 70D, it may be used in stage position measurement. In that case, a section of the Y-coordinate of the wafer stage WST X heads 66 ₀ and X scale 39X ₂ are opposed, and the X heads 66 ₅ and X scales 39X ₁ is Y coordinate of the wafer stage WST opposing sections, substantially coincide Therefore, there is an advantage that sufficient connection accuracy can be ensured in the switching process between the X encoders 70B and 70D.

Further, the X heads 66 ₀ for calibration, from the head 66 ₅ of the most -Y side belonging to head units 62B, it may be provided at a distance WD in the -Y direction. Here, the distance between the X heads 66 ₀ and 66 ₄ is selected to be approximately equal to the distance between the X scales 39X ₁ and 39X ₂ . It is also possible to calibrate the X encoders 70B and 70D using the X heads 66 ₀ and 66 ₄ according to the same procedure as the calibration method using the X heads 66 ₀ and 66 ₅ described above. Incidentally, including the X heads 66 ₀ to the head unit 62B, as a component of X encoders 70B, may be used in stage position measurement. In this case, as described above, the Y coordinate section of wafer stage WST where X head 66 ₀ and X scale 39X ₁ face _each other, and the Y coordinate section of wafer stage WST where X head 66 ₄ and X scale 39X ₂ face _each other. Are substantially coincident with each other, and therefore there is an advantage that sufficient connection accuracy can be ensured in the switching process between the X encoders 70B and 70D.

Further, instead of providing the X heads 66 ₀ for calibration, X encoders 70B, the arrangement interval in the Y-axis direction 70D, narrowing the X heads 66 _0, 66 ₅ Y spacing in this embodiment, and, X head 66 _0, 66 instead of _5, X encoder 70B using X head 66 _4, 66 _5, may be calibrated 70D. When this X head arrangement is adopted, the Y coordinate section of the stage WST where the X head 66 ₄ and the X scale 39X ₂ face each other, and the stage WST where the X head 66 ₅ and the X scale 39X ₁ face _{each other} , as described above. Therefore, there is an advantage that sufficient connection accuracy can be secured in the switching process between the X encoders 70B and 70D.

Further, in the calibration method according to the present embodiment, the relationship between the measurement values of the X heads 66 ₅ and 66 ₀ is obtained, and calibration data is created from the relationship, so measurement is not necessarily performed on the X scales 39X ₁ and 39X ₂ at equal intervals. There is no need to arrange the points.

  Note that the configuration of each measuring apparatus such as the encoder system described in the above embodiment is merely an example, and the present invention is of course not limited thereto. For example, in the above-described embodiment, an encoder system having a configuration in which a lattice unit (Y scale, X scale) is provided on a wafer table (wafer stage), and an X head and a Y head are arranged outside the wafer stage so as to face the lattice unit. Although the case where it is adopted is illustrated, the present invention is not limited to this, and as disclosed in, for example, US Patent Application Publication No. 2006/0227309, an encoder head is provided on the wafer stage, and the wafer stage is opposed to the encoder head. You may employ | adopt the encoder system of the structure which arrange | positions a grating | lattice part (For example, the two-dimensional grating | lattice or the two-dimensionally arranged one-dimensional grating | lattice part) outside. In this case, the Z head may also be provided on the wafer stage, and the surface of the lattice portion may be a reflective surface to which the measurement beam of the Z head is irradiated.

  In the above embodiment, the case where the present invention is applied to a scanning exposure apparatus such as a step-and-scan method has been described. However, the present invention is not limited to this, and the present invention is applied to a stationary exposure apparatus such as a stepper. May be. Even in the case of a stepper or the like, the same effect can be obtained because the position of the stage on which the object to be exposed is mounted can be measured using the encoder as in the above embodiment. The present invention can also be applied to a step-and-stitch reduction projection exposure apparatus, a proximity exposure apparatus, or a mirror projection aligner that synthesizes a shot area and a shot area. In addition, as disclosed in, for example, US Pat. No. 6,590,634, US Pat. No. 5,969,441, US Pat. No. 6,208,407, a plurality of wafers. The present invention can also be applied to a multi-stage type exposure apparatus provided with a stage.

  In addition, the projection optical system in the exposure apparatus of the above embodiment may be not only a reduction system but also an equal magnification and an enlargement system, and the projection optical system PL may be not only a refraction system but also a reflection system or a catadioptric system. The projected image may be either an inverted image or an erect image. In addition, the illumination area and the exposure area described above are rectangular in shape, but the shape is not limited to this, and may be, for example, an arc, a trapezoid, or a parallelogram.

The light source of the exposure apparatus of the above embodiment is not limited to the ArF excimer laser, but is a KrF excimer laser (output wavelength 248 nm), F ₂ laser (output wavelength 157 nm), Ar ₂ laser (output wavelength 126 nm), Kr ₂ laser ( It is also possible to use a pulse laser light source with an output wavelength of 146 nm, an ultrahigh pressure mercury lamp that emits a bright line such as g-line (wavelength 436 nm), i-line (wavelength 365 nm), and the like. A harmonic generator of a YAG laser or the like can also be used. In addition, as disclosed in, for example, US Pat. No. 7,023,610, a single wavelength laser beam in an infrared region or a visible region oscillated from a DFB semiconductor laser or a fiber laser is used as vacuum ultraviolet light. For example, a harmonic that is amplified by a fiber amplifier doped with erbium (or both erbium and ytterbium) and wavelength-converted into ultraviolet light using a nonlinear optical crystal may be used.

  In the above embodiment, it is needless to say that the illumination light IL of the exposure apparatus is not limited to light having a wavelength of 100 nm or more, and light having a wavelength of less than 100 nm may be used. For example, the present invention is also suitable for an EUV exposure apparatus that uses EUV (Extreme Ultraviolet) light in a soft X-ray region (for example, a wavelength region of 5 to 15 nm) as exposure light and uses an all-reflection reduction optical system and a reflective mask. Can be applied. In addition, the present invention can be applied to an exposure apparatus using a charged particle beam such as an electron beam or an ion beam.

  In the above-described embodiment, a light transmission mask (reticle) in which a predetermined light-shielding pattern (or phase pattern / dimming pattern) is formed on a light-transmitting substrate is used. Instead of this reticle, For example, as disclosed in US Pat. No. 6,778,257, an electronic mask (variable shaping mask, which forms a transmission pattern, a reflection pattern, or a light emission pattern based on electronic data of a pattern to be exposed, as disclosed in US Pat. No. 6,778,257. For example, a non-light emitting image display element (spatial light modulator) including a DMD (Digital Micro-mirror Device) may be used.

  Further, for example, the present invention can be applied to an exposure apparatus (lithography system) that forms line and space patterns on a wafer by forming interference fringes on the wafer.

  Further, as disclosed in, for example, US Pat. No. 6,611,316, two reticle patterns are synthesized on a wafer via a projection optical system, and one scan exposure is performed on one wafer. The present invention can also be applied to an exposure apparatus that performs double exposure of shot areas almost simultaneously.

  The apparatus for forming a pattern on an object is not limited to the above-described exposure apparatus (lithography system), and the present invention can also be applied to an apparatus for forming a pattern on an object by, for example, an inkjet method.

  Note that the object on which the pattern is to be formed in the above embodiment (the object to be exposed to the energy beam) is not limited to the wafer, but other objects such as a glass plate, a ceramic substrate, a film member, or a mask blank. But it ’s okay.

  The use of the exposure apparatus is not limited to the exposure apparatus for semiconductor manufacturing. For example, an exposure apparatus for liquid crystal that transfers a liquid crystal display element pattern onto a square glass plate, an organic EL, a thin film magnetic head, an image sensor ( CCDs, etc.), micromachines, DNA chips and the like can also be widely applied to exposure apparatuses. Further, in order to manufacture reticles or masks used in not only microdevices such as semiconductor elements but also light exposure apparatuses, EUV exposure apparatuses, X-ray exposure apparatuses, electron beam exposure apparatuses, etc., glass substrates or silicon wafers, etc. The present invention can also be applied to an exposure apparatus that transfers a circuit pattern.

  An electronic device such as a semiconductor element includes a step of designing a function / performance of the device, a step of manufacturing a reticle based on the design step, a step of manufacturing a wafer from a silicon material, and the exposure apparatus (pattern forming apparatus) of the above-described embodiment. ) A lithography step for transferring a mask (reticle) pattern onto a wafer, a development step for developing the exposed wafer, an etching step for removing exposed members other than the portion where the resist remains by etching, and etching is completed. It is manufactured through a resist removal step for removing unnecessary resist, a device assembly step (including a dicing process, a bonding process, and a package process), an inspection step, and the like. In this case, in the lithography step, the exposure method described above is executed using the exposure apparatus of the above embodiment, and a device pattern is formed on the wafer. Therefore, a highly integrated device can be manufactured with high productivity.

  The calibration method of the present invention, and the mobile object driving method and apparatus for driving the mobile object by applying the calibration method are suitable for driving the mobile object. The exposure method and apparatus of the present invention are suitable for forming a pattern on an object by irradiating an energy beam. The pattern forming method and apparatus of the present invention are suitable for forming a pattern on an object. The device manufacturing method of the present invention is suitable for manufacturing an electronic device such as a semiconductor element or a liquid crystal display element.

It is a figure which shows schematically the structure of the exposure apparatus which concerns on one Embodiment. 2A is a plan view showing the wafer stage, and FIG. 2B is a plan view showing the measurement stage. It is a top view which shows arrangement | positioning of the stage apparatus with which the exposure apparatus of FIG. 1 is equipped, and an interferometer. It is a top view which shows arrangement | positioning of the stage apparatus with which the exposure apparatus of FIG. 1 is equipped, and measuring devices. It is a top view which shows arrangement | positioning of an encoder head (X head, Y head) and an alignment system. It is a top view which shows arrangement | positioning of Z head and a multipoint AF type | system | group. It is a block diagram which shows the main structures of the control system of the exposure apparatus which concerns on one Embodiment. FIGS. 8A and 8B are views for explaining wafer table position measurement and switching between heads using an encoder composed of a plurality of heads. It is a figure for demonstrating switching between the X head which belongs to the head unit 62B, and the X head which belongs to the head unit 62D. It is FIG. (1) for demonstrating the comparative measurement using the X head for a calibration for calibrating X encoder 70B, 70D. It is FIG. (2) for demonstrating the comparative measurement using the X head for a calibration for calibrating X encoder 70B, 70D.

Explanation of symbols

20 ... main control unit, 39X _1, 39X ₂ ... X scales 39Y _1, 39Y ₂ ... Y scale, 50 ... stage device, 62a to 62f ... head unit, 64 and 65 ... Y head, 66 ... X heads 67, 68 ... Y head, 70A, 70C ... Y encoder, 70B, 70D ... X encoder, 100 ... exposure apparatus, 118 ... interferometer system, 124 ... stage drive system, 150 ... encoder system, 200 ... measuring system, W ... wafer, WST ... wafer stage, WTB ... wafer table.

Claims (27)

A calibration method for calibrating the accuracy of driving a moving body along a predetermined plane including a first axis and a second axis orthogonal to each other,
A second direction parallel to the second axis provided by driving the movable body and spaced apart in a first direction parallel to the first axis on a surface substantially parallel to the predetermined plane of the movable body Measuring the position of the moving body in the second direction using a plurality of first and second encoder heads that can respectively face the first and second gratings having a periodic direction of Using a pair of encoder heads facing each of the third and fourth gratings having the first direction as a periodic direction provided on one surface and spaced apart in the second direction, the moving body related to the first direction is arranged. Measuring the position;
Creating calibration data for calibrating measured values of at least one of the pair of encoder heads using measurement results of the first and second encoder heads and the pair of encoder heads;
A calibration method comprising:   In the creating step, the calibration data is obtained by measuring the position of the movable body in the first direction and the second direction, or the measurement points of the pair of encoder heads on the third and fourth gratings. The calibration method according to claim 1, wherein the calibration method is created as a two-dimensional function of a first direction and a position in the second direction.   2. The calibration data is created in consideration of the position of the moving body with respect to an axis orthogonal to the predetermined plane derived from the measurement results of the first and second encoder heads in the creating step. 3. The calibration method according to 2.   The calibration method according to claim 3, wherein, in the creating step, calibration data for calibrating the other measured value is created based on one measured value of the pair of encoder heads.   The calibration method according to claim 3, wherein, in the creating step, calibration data for calibrating the measurement values of both the pair of encoder heads with reference to an average value of the measurement values is created.   In the creating step, a first calculation result of a position in the predetermined plane of the movable body derived from a measurement result of one of the first and second encoder heads and the pair of encoder heads, and the first Generating the calibration data using a second calculation result of a position of the movable body in the predetermined plane derived from a measurement result of the other of the second encoder head and the pair of encoder heads. Item 3. The calibration method according to Item 1 or 2.   The calibration method according to claim 6, wherein, in the creating step, the calibration data for calibrating the other of the first calculation result and the second calculation result is used as a reference.   The said creation process WHEREIN: The said calibration data for calibrating said 1st calculation result and said 2nd calculation result on the basis of the average value of both these calculation results is created. Calibration method.   The said measurement process WHEREIN: The said moving body is driven based on the measurement result of at least one of the pair of encoder heads, and the first and second encoder heads. The calibration method according to 1.   The measuring step includes measuring a position of the moving body within the predetermined plane using a measuring system including an interferometer, and driving the moving body based on a measurement result of the measuring system. The calibration method according to any one of 1 to 8. The step of creating includes
Creating a partial data corresponding to a part of the calibration data using the measurement results when the measurement results of the pair of encoder heads are updated;
Updating at least a portion of the calibration data using the partial data or the set of partial data;
The calibration method according to claim 1, comprising: A moving body driving method for driving a moving body along a predetermined plane including a first axis and a second axis orthogonal to each other,
A first direction having a second direction parallel to the second axis, spaced apart in a first direction parallel to the first axis, on one surface of the movable body substantially parallel to the predetermined plane and having a periodic direction; Using the first and second head units including a plurality of first and second encoder heads that can respectively face the second grating, the position of the moving body in the second direction is measured, and The third and fourth encoder heads include a plurality of third and fourth encoder heads that can face the third and fourth gratings, respectively, having the first direction provided in the one surface and spaced apart in the second direction. Measuring the position of the moving body in the first direction using at least one of the four head units;
A step of driving the moving body based on a measurement result of the measuring step and calibration data created using the calibration method according to any one of claims 1 to 11;
A moving body drive method including:   The moving body drive method according to claim 12, further comprising a step of switching an encoder head to be used between the third and fourth head units according to the position of the moving body.   In the switching step, the moving body includes a first moving region of the moving body in which the third encoder head faces the third grating, and a moving body of the moving body in which the fourth encoder head faces the fourth grating. The second moving area is used after switching so that the measured value of the position of the moving body is maintained before and after switching while the two moving areas move through the overlapping area. The moving body drive method according to claim 13, wherein the measurement value of the encoder head is reset. An exposure method for irradiating an energy beam to form a pattern on an object,
An exposure method including a step of driving a moving body that holds the object using the moving body driving method according to any one of claims 12 to 14 in order to form the pattern. A pattern forming method for forming a pattern on an object,
The pattern formation method including the process of driving the moving body holding the said object along a predetermined plane using the moving body drive method as described in any one of Claims 12-14 in order to form the said pattern. . The object has a sensitive layer;
The pattern forming method according to claim 16, wherein the pattern is formed by irradiating the sensitive layer with an energy beam.   The pattern forming method according to claim 17, wherein the energy beam is irradiated through an optical system and a liquid supplied between the optical system and the object. A step of forming a pattern on the object using the pattern forming method according to any one of claims 16 to 18;
Processing the object on which the pattern is formed;
A device manufacturing method including: A moving body drive apparatus for driving a moving body along a predetermined plane including a first axis and a second axis orthogonal to each other,
A first direction having a second direction parallel to the second axis, spaced apart in a first direction parallel to the first axis, on one surface of the movable body substantially parallel to the predetermined plane and having a periodic direction; First and second head units that have a plurality of first and second encoder heads that can respectively face the second grating and that measure the position of the moving body in the second direction;
There are a plurality of third and fourth encoder heads that can be opposed to the third and fourth gratings, each of which is provided on the one surface of the moving body and spaced apart in the second direction, and whose first direction is the periodic direction. And third and fourth head units for measuring the position of the moving body in the first direction;
A storage device for storing calibration data created using the calibration method according to claim 1;
A drive device for driving the movable body based on the measurement result of at least one of the first and second head units and the third and fourth head units and the calibration data;
A moving body drive apparatus comprising:   Among the plurality of third and fourth encoder heads, a separation distance in the second direction of at least a pair of the third and fourth encoder heads is a separation distance of the third and fourth gratings in the second direction; 21. The moving body drive apparatus according to claim 20, which is substantially equal.   The moving body drive device according to claim 20 or 21, further comprising a switching device that switches an encoder head to be used between the third and fourth head units according to the position of the moving body.   In the switching device, the moving body includes a first moving area of the moving body in which the third encoder head faces the third grating, and a moving body of the moving body in which the fourth encoder head faces the fourth grating. The second moving area is used after switching so that the measured value of the position of the moving body is maintained before and after switching while the two moving areas move through the overlapping area. The moving body drive device according to claim 22, wherein the measurement value of the encoder head is reset. An exposure apparatus that irradiates an energy beam to form a pattern on an object,
24. An exposure apparatus comprising a moving body driving device according to claim 20, wherein a moving body that holds the object is driven along a predetermined plane to form the pattern. A pattern forming apparatus for forming a pattern on an object,
A movable body that holds and moves the object;
A pattern generator for forming a pattern on the object;
The moving body drive device according to any one of claims 20 to 23, wherein the moving body is driven along a predetermined plane;
A pattern forming apparatus comprising: The object has a sensitive layer;
26. The pattern forming apparatus according to claim 25, wherein the pattern generating apparatus forms the pattern by irradiating the sensitive layer with an energy beam. The pattern generation apparatus includes an optical system,
27. The pattern forming apparatus according to claim 26, further comprising a liquid supply device that supplies a liquid between the optical system and the object.

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